Automated systems for cutting mat board and the like, which operate under computer control (CNC matcutters), are known in the art and are commercially available. (See for example the article entitled xe2x80x9cComputerized Automated Matcuttersxe2x80x9d by Robert Palmer, PFM Magazine, May 1995, pages 66-86.) The cutting head employed in such apparatus typically has an associated glide plate that surrounds the tip of the blade, which facilitates movement over the board and improves cutting.
A difficultly that arises due to the presence of such a glide plate concerns interference with elements used for clamping the workpiece in place against the machine table. The clamping elements not only limit the closeness of approach of the blade to the edge of the board, and consequently border width, but they also preclude sizing (i.e., cutting of a smaller piece of mat board from a larger one) because the blade cannot move all the way to the edge of the workpiece.
Other deficiencies that are typically present in matcutters of the prior art concern operation of the head itself. For example, the motion of the head components by which blade plunging is effected is often not sufficiently smooth and well-controlled to enable the production of optimal cuts, and the construction often does not afford facile and precise relative positioning of the parts comprising the head.
Accordingly, it is a broad object of the present invention to provide a novel cutting head assembly suitable for use in a matcutter, and especially a computerized automated matcutter, wherein operation of the components is smooth and well controlled, and wherein the construction affords facile and precise relative positioning and repositioning.
It has now been found that the forgoing and related objects of the invention are readily attained by the provision of a head assembly for a mat cutting machine, comprising a head having mounting-means for movement of the assembly on an axis, and defining a first channel oriented at an oblique angle to the axis; a slide mounted for slidable movement in the head channel, between a withdrawn blade position and a plunged blade position, the slide having a second channel therein extending substantially parallel to the first channel for receiving a blade-holding magazine inserted thereinto; and such a magazine dimensioned and configured for slidable insertion into the second channel of the slide. The slide and head have first cooperating mechanical means thereon for adjustably limiting the movement of the slide to the plunged blade position, and the slide and magazine have second cooperating mechanical means thereon for adjustably limiting the depth of magazine insertion in the second channel.
The head assembly will preferably include a linear motion support system for the slide, which support system comprises, on each of two opposite sides of the slide, an array of at least three elongate rectilinear elements mutually spaced to define a passage therewithin, and a multiplicity of bearing elements loosely stacked within the defined passage. The slide may advantageously have a boss defining a threaded aperture that opens to the second channel, with a tightening screw received within the aperture for clampingly engaging a cutting blade received in the magazine. Most desirably, the assembly will comprise at least a second magazine, with a locating component of the second cooperating means on the first-mentioned magazine being disposed differently from the corresponding locating component on the second magazine, and with the slide having separate abutment components for independently engaging each of the locating components of the first and second magazines.